This invention relates to a method for predicting destruction of devices such as a bearing with the aid of acoustic emission.
Conventionally, a method of detecting abnormality in a bearing with the aid of acoustic emission has been utilized only for plain bearings. For example, the abnormality can be found out by detecting acoustic emission generated by damage on a metal surface caused by the friction generated between a sleeve and a bush when a lubricant film on a plain bearing is removed.
The above-described conventional method of detecting abnormality in a bearing is used, however, only to detect damage already existing on the surface of the sleeve or bush of a plain bearing, thus no preliminary indication can be detected by this method.
Accordingly, bearings required to ensure a stable operation such as, for example, bearings for an aircraft and a vehicle which may directly lead to fatal accidents, and bearings for water equipment and electrical power generators, which must work continuously for 24 hours without accidents, have been replaced frequently to achieve a high safety factor, i.e., even bearings which can continue to function well have been replaced and disposed. Some bearings are destroyed despite having sufficient safety factors, thus, resulting in a great deal of economical loss.